Many of this catshark are contaminated by DDT
The Cloudy catshark (Scyliorhinus torazame) is a species of catshark, belonging to the family Scyliorhinidae. It inhabits rocky reefs in the northwestern Pacific Ocean, from the shore to a depth of 1,050 feet. This small, slim shark has a narrow head with a short blunt snout, no grooves between the nostrils and mouth, and furrows on the lower but not the upper jaw. There are dark brown saddles along the back and tail, and it has very rough skin to the touch.
Family: Scyliorhinidae – Catsharks
Common Name– Ground Sharks
Common Name– Catsharks
Average Size and Length: Each egg case measures 2 x 6 cm long. Hatchlings measure over 8 cm/ 3 inches long. Mature males measure between 41-48 cm/1.3-1.5 feet, and mature females over 39 cm/1.2 feet long. The longest recorded is 48 cm/1.5 feet.
Current Rare Mythical Sightings: The original description of the Cloudy catshark was published in 1908 by Shigeho Tanaka in the Journal of the Faculty of Science, University of Tokyo. The specific epithet torazame, is its Japanese name (虎鮫, “tiger shark“). It was assigned to the genus Catulus. The type specimen was a 45 cm/1.4 feet long adult male caught off Misaki, Kanagawa, Japan. Subsequent authors have synonymized Catulus with Scyliorhinus.
Teeth and Jaw: The labial furrows are on the lower jaw only. The small teeth have one very large, straight, pointed and fat central cusp, with four surrounding small cusplets, totaling five.
Head: The head is narrow, and the snout is short and blunt. The head makes up slightly under one-sixth of the total length and is two-thirds as wide as it is long. The small anterior nasal flaps do not reach the mouth. There are no nasoral grooves. The medium-sized eyes are horizontally oval, with nictitating membranes and followed by spiracles.
Denticles: The skin is very thick and rough. The dermal denticles are large and upright with three backward-pointing teeth.
Demographic, Distribution, Habitat, Environment and Range: The Cloudy catshark can be found in the northwest Pacific in Japan in Hokkaido and Honshu to Okinawa, in Korea, in China, and possibly the Philippines (40°N – 22°N). They can be found on the continental shelf and upper slope close inshore to at least 1,050 feet. One nursery area is located at a depth of 330 feet off Hakodate. They are considered tropical, demersal.
Diet: More than likely it eats crustaceans, mollusks and bony fish.
Aesthetic Identification: The Cloudy catshark is small, slender, firm and deep, with six to nine darker saddles and in larger sharks, many irregular large dark and light spots on dark skin. The five pairs of gill slits are short, with the fourth pair over the pectoral fin origins. The two dorsal fins are placed towards the back of the body, with the first originating over the rear of the pelvic fin bases. The second dorsal fin is much smaller and angular than the first dorsal fin, which has a rounded apex. The pectoral and pelvic fins are moderate in size. In males, the inner margins of the pelvic fins are merged to form an apron over the long, cylindrical claspers. The origin of the anal fin lies approximately between the dorsal fins. The claspers of the male Cloudy catshark have numerous hooks that likely serve to facilitate copulation.
Biology and Reproduction: They are oviparous having one egg per oviduct. Egg cases are deposited in a nursery or in a hatching ground. The egg cases are smooth, translucent yellow, vase-shaped capsules.There are long tendrils at the four corners of the capsule.
The female is capable of storing sperm within her nidamental gland for many months.
More than likely, like in the Japanese catshark, when the embryo is 3.6 cm/1.4 inches long, it has external gills, undeveloped fins, and no pigmentation. At an embryonic length of 5.8 cm/2.3 inches, the external gills have all but disappeared, and a covering of small denticles is present. By a length of 7.9 cm/3.1 inches, the embryo has well-developed fins and pigmentation, and generally resembles the adult.
The eggs take 15 months to hatch at 52.3 °F, and 7–9 months to hatch at 58.1 °F.
Off northerly Hakodate, both sexes mature at over 38 cm/ 1.2 feet long, while some females remain immature even at 47 cm/1.5 feet long. By contrast, off southerly Tsushima Island both sexes mature at around 33 cm/ 1 foot long. The maximum lifespan is at least 12 years.
A known parasite of this species is the myxosporidian Chloromyxum scyliorhinum.
On September 25, 1995, Masuda Motoyashi and colleagues used this species to perform the first successful artificial insemination of a shark or ray. (Motoyasu, M.; I. Yoshiyuki; K. Shigenori; I. Haruyuki & I. Tooru (2003). “Artificial insemination of the cloudy catshark“. Journal of Japanese Association of Zoological Gardens and Aquariums. 44 (2): 39–43.).
Behavioral Traits, Sensing and Intelligence: Just before they are about to mate, the male bites at the female’s pectoral fin, side, and gill region. Once he has a grip, he wraps his body around hers and inserts one of his claspers into her cloaca. Copulation may last between 15 seconds and 4 minutes.
Cloudy Catshark Future and Conservation: They are currently of least concern. It is often kept in captivity and used in many biological research projects. It is caught incidentally and discarded as bycatch by commercial fisheries. They are hardy and have a high survival rate. Around 40% of the fish discarded in Yamaguchi Prefecture fisheries are of the Cloudy catshark. They may catch over a ton annually.
Cloudy catsharks from a number of locations off Japan have been found to be contaminated with polychlorinated biphenyls (PCBs) and dichlorodiphenyldichloroethylene (DDEs), which they acquire from their food. One likely source of these pollutants is the use of the pesticide DDT by developing nations in southern Asia. (Horie, T.; H. Tanaka & S. Tanaka (2004). “Bioaccumulation of PCBs and DDE in cloudy catshark, Scyliorhinus torazame, caught in four locations around Japan”. Journal of the School of Marine Science and Technology Tokai University. 2 (2): 33–43).
Cloudy Catshark Recorded Attacks on Humans: Not a threat to humans.